Abstract:
Probably any chemist must have dreamt about it: Quick isolation of a chemical from a reaction mixture without the hassle of tedious liquid handling lasting for hours. The problem is that today the product separation and postprocessing of organic compounds, proteins, nucleic acids, and natural products from complex reaction mixtures remains labor-intensive and costly. Catalytic processes in the liquid phase are important in many areas of the fine and specialty chemicals industries, and the use of solid catalysts means easier catalyst separation and recovery, hence facilitating their reuse. Usually a smaller catalyst particles means a higher activity, and sub micron particles are particularly attractive because they experience no significant attrition, i.e. no reduction in particle size. A major difficultly with small particles is the cumbersome fact that they are almost impossible to separate by conventional means, which can lead to the blocking of filters and valves by the catalyst. A possible solution to this problem is the magnetic separation of products from mixtures, as routinely applied in biochemistry. Unfortunately, the exorbitant price of magnetic microbeads and their low binding capacity limit their use for organic synthesis. Researchers in Switzerland, have now found a way to link organic molecules to metallic nanomagnets. This allows separating tagged molecules or reagents after synthesis within seconds. The technology is now explored in organic chemistry and biotechnology as an alternative to chromatography or crystallization. Combining classical organic synthesis or polymer production with magnetic separation could potentially revolutionize key processes in the chemical industry.